[ He'll take the spear from her and feel it out, but he still doesn't actually say much. It's clear that he's listening, but he doesn't seem up for arguing her points or really revealing what he's thinking at all. He just seems tired, really. ]

I have no idea, honestly. My friend is dead, so it's my duty to examine every possibility. Surely you understand that, yes?

[ He starts to step away, so long as Undyne doesn't stop him. He's just going to head towards the body, since he'll go do his best to compare the two since he has the spear in hand anyways. Might as well... ]

So, if you'll excuse me. I'll return this in a moment.